Self-repairing ceramic for aircraft engines

Japanese researchers claim to have developed a ceramic material that self-repairs cracks in just one minute and could drastically change manufacturing methods for the transportation industry.

The team from the National Institute for Materials Science (NIMS) and Yokohama National University, Japan said the material could be used in aeroplane engines to keep them operating even if they are damaged in collisions with airborne objects.

Toshio Osada, a senior researcher at the NIMS, said: “When the plane engine suffers a crack during a flight, the ceramic material will enable the aircraft to repair the damage by itself before landing without stopping the engine.”

Wataru Nakao, an engineering professor at the university, said the material “can be used for a wide variety of products,” and the team is planning studies to commercialise it.

Ceramic-made engines have been seen as a possible way to improve fuel-efficiency as it is lighter and more heat resistant than nickel and titanium, but was considered too fragile for use in aircraft engines.

To solve the problem, the researchers added silicon carbide to a ceramic material made of aluminium oxide. When the ceramic cracked at high temperatures, the silicon carbide was exposed to air and turned into silicon dioxide that filled in the crack and repaired the damage.

The self-healing process initially required around 1000 hours to complete, but the NIMS researchers have now reduced the time to one minute under temperatures of 1000°C by adding a tiny amount of manganese oxide which they said promotes the phenomenon.

The scientists said they are working on improvements so that the material can repair damage at lower temperatures, making it possible for use in the undercarriages of Shinkansen bullet trains.